Novin said the added expense will drive many people away from a sport that is part of American heritage.

CNN: Should hunters switch to 'green' bullets?

Available studies -- particularly the one from North Dakota -- prove that point, said Ted Novin, spokesman for National Shooting Sports Foundation.

CNN: Should hunters switch to 'green' bullets?

Pickard said Novin's group is misrepresenting science.

CNN: Should hunters switch to 'green' bullets?